Loading...
1# SPDX-License-Identifier: GPL-2.0-only
2menuconfig MODULES
3 bool "Enable loadable module support"
4 modules
5 help
6 Kernel modules are small pieces of compiled code which can
7 be inserted in the running kernel, rather than being
8 permanently built into the kernel. You use the "modprobe"
9 tool to add (and sometimes remove) them. If you say Y here,
10 many parts of the kernel can be built as modules (by
11 answering M instead of Y where indicated): this is most
12 useful for infrequently used options which are not required
13 for booting. For more information, see the man pages for
14 modprobe, lsmod, modinfo, insmod and rmmod.
15
16 If you say Y here, you will need to run "make
17 modules_install" to put the modules under /lib/modules/
18 where modprobe can find them (you may need to be root to do
19 this).
20
21 If unsure, say Y.
22
23if MODULES
24
25config MODULE_DEBUGFS
26 bool
27
28config MODULE_DEBUG
29 bool "Module debugging"
30 depends on DEBUG_FS
31 help
32 Allows you to enable / disable features which can help you debug
33 modules. You don't need these options on production systems.
34
35if MODULE_DEBUG
36
37config MODULE_STATS
38 bool "Module statistics"
39 depends on DEBUG_FS
40 select MODULE_DEBUGFS
41 help
42 This option allows you to maintain a record of module statistics.
43 For example, size of all modules, average size, text size, a list
44 of failed modules and the size for each of those. For failed
45 modules we keep track of modules which failed due to either the
46 existing module taking too long to load or that module was already
47 loaded.
48
49 You should enable this if you are debugging production loads
50 and want to see if userspace or the kernel is doing stupid things
51 with loading modules when it shouldn't or if you want to help
52 optimize userspace / kernel space module autoloading schemes.
53 You might want to do this because failed modules tend to use
54 up significant amount of memory, and so you'd be doing everyone a
55 favor in avoiding these failures proactively.
56
57 This functionality is also useful for those experimenting with
58 module .text ELF section optimization.
59
60 If unsure, say N.
61
62config MODULE_DEBUG_AUTOLOAD_DUPS
63 bool "Debug duplicate modules with auto-loading"
64 help
65 Module autoloading allows in-kernel code to request modules through
66 the *request_module*() API calls. This in turn just calls userspace
67 modprobe. Although modprobe checks to see if a module is already
68 loaded before trying to load a module there is a small time window in
69 which multiple duplicate requests can end up in userspace and multiple
70 modprobe calls race calling finit_module() around the same time for
71 duplicate modules. The finit_module() system call can consume in the
72 worst case more than twice the respective module size in virtual
73 memory for each duplicate module requests. Although duplicate module
74 requests are non-fatal virtual memory is a limited resource and each
75 duplicate module request ends up just unnecessarily straining virtual
76 memory.
77
78 This debugging facility will create pr_warn() splats for duplicate
79 module requests to help identify if module auto-loading may be the
80 culprit to your early boot virtual memory pressure. Since virtual
81 memory abuse caused by duplicate module requests could render a
82 system unusable this functionality will also converge races in
83 requests for the same module to a single request. You can boot with
84 the module.enable_dups_trace=1 kernel parameter to use WARN_ON()
85 instead of the pr_warn().
86
87 If the first module request used request_module_nowait() we cannot
88 use that as the anchor to wait for duplicate module requests, since
89 users of request_module() do want a proper return value. If a call
90 for the same module happened earlier with request_module() though,
91 then a duplicate request_module_nowait() would be detected. The
92 non-wait request_module() call is synchronous and waits until modprobe
93 completes. Subsequent auto-loading requests for the same module do
94 not trigger a new finit_module() calls and do not strain virtual
95 memory, and so as soon as modprobe successfully completes we remove
96 tracking for duplicates for that module.
97
98 Enable this functionality to try to debug virtual memory abuse during
99 boot on systems which are failing to boot or if you suspect you may be
100 straining virtual memory during boot, and you want to identify if the
101 abuse was due to module auto-loading. These issues are currently only
102 known to occur on systems with many CPUs (over 400) and is likely the
103 result of udev issuing duplicate module requests for each CPU, and so
104 module auto-loading is not the culprit. There may very well still be
105 many duplicate module auto-loading requests which could be optimized
106 for and this debugging facility can be used to help identify them.
107
108 Only enable this for debugging system functionality, never have it
109 enabled on real systems.
110
111config MODULE_DEBUG_AUTOLOAD_DUPS_TRACE
112 bool "Force full stack trace when duplicates are found"
113 depends on MODULE_DEBUG_AUTOLOAD_DUPS
114 help
115 Enabling this will force a full stack trace for duplicate module
116 auto-loading requests using WARN_ON() instead of pr_warn(). You
117 should keep this disabled at all times unless you are a developer
118 and are doing a manual inspection and want to debug exactly why
119 these duplicates occur.
120
121endif # MODULE_DEBUG
122
123config MODULE_FORCE_LOAD
124 bool "Forced module loading"
125 default n
126 help
127 Allow loading of modules without version information (ie. modprobe
128 --force). Forced module loading sets the 'F' (forced) taint flag and
129 is usually a really bad idea.
130
131config MODULE_UNLOAD
132 bool "Module unloading"
133 help
134 Without this option you will not be able to unload any
135 modules (note that some modules may not be unloadable
136 anyway), which makes your kernel smaller, faster
137 and simpler. If unsure, say Y.
138
139config MODULE_FORCE_UNLOAD
140 bool "Forced module unloading"
141 depends on MODULE_UNLOAD
142 help
143 This option allows you to force a module to unload, even if the
144 kernel believes it is unsafe: the kernel will remove the module
145 without waiting for anyone to stop using it (using the -f option to
146 rmmod). This is mainly for kernel developers and desperate users.
147 If unsure, say N.
148
149config MODULE_UNLOAD_TAINT_TRACKING
150 bool "Tainted module unload tracking"
151 depends on MODULE_UNLOAD
152 select MODULE_DEBUGFS
153 help
154 This option allows you to maintain a record of each unloaded
155 module that tainted the kernel. In addition to displaying a
156 list of linked (or loaded) modules e.g. on detection of a bad
157 page (see bad_page()), the aforementioned details are also
158 shown. If unsure, say N.
159
160config MODVERSIONS
161 bool "Module versioning support"
162 help
163 Usually, you have to use modules compiled with your kernel.
164 Saying Y here makes it sometimes possible to use modules
165 compiled for different kernels, by adding enough information
166 to the modules to (hopefully) spot any changes which would
167 make them incompatible with the kernel you are running. If
168 unsure, say N.
169
170config ASM_MODVERSIONS
171 bool
172 default HAVE_ASM_MODVERSIONS && MODVERSIONS
173 help
174 This enables module versioning for exported symbols also from
175 assembly. This can be enabled only when the target architecture
176 supports it.
177
178config MODULE_SRCVERSION_ALL
179 bool "Source checksum for all modules"
180 help
181 Modules which contain a MODULE_VERSION get an extra "srcversion"
182 field inserted into their modinfo section, which contains a
183 sum of the source files which made it. This helps maintainers
184 see exactly which source was used to build a module (since
185 others sometimes change the module source without updating
186 the version). With this option, such a "srcversion" field
187 will be created for all modules. If unsure, say N.
188
189config MODULE_SIG
190 bool "Module signature verification"
191 select MODULE_SIG_FORMAT
192 help
193 Check modules for valid signatures upon load: the signature
194 is simply appended to the module. For more information see
195 <file:Documentation/admin-guide/module-signing.rst>.
196
197 Note that this option adds the OpenSSL development packages as a
198 kernel build dependency so that the signing tool can use its crypto
199 library.
200
201 You should enable this option if you wish to use either
202 CONFIG_SECURITY_LOCKDOWN_LSM or lockdown functionality imposed via
203 another LSM - otherwise unsigned modules will be loadable regardless
204 of the lockdown policy.
205
206 !!!WARNING!!! If you enable this option, you MUST make sure that the
207 module DOES NOT get stripped after being signed. This includes the
208 debuginfo strip done by some packagers (such as rpmbuild) and
209 inclusion into an initramfs that wants the module size reduced.
210
211config MODULE_SIG_FORCE
212 bool "Require modules to be validly signed"
213 depends on MODULE_SIG
214 help
215 Reject unsigned modules or signed modules for which we don't have a
216 key. Without this, such modules will simply taint the kernel.
217
218config MODULE_SIG_ALL
219 bool "Automatically sign all modules"
220 default y
221 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
222 help
223 Sign all modules during make modules_install. Without this option,
224 modules must be signed manually, using the scripts/sign-file tool.
225
226comment "Do not forget to sign required modules with scripts/sign-file"
227 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
228
229choice
230 prompt "Which hash algorithm should modules be signed with?"
231 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
232 help
233 This determines which sort of hashing algorithm will be used during
234 signature generation. This algorithm _must_ be built into the kernel
235 directly so that signature verification can take place. It is not
236 possible to load a signed module containing the algorithm to check
237 the signature on that module.
238
239config MODULE_SIG_SHA256
240 bool "Sign modules with SHA-256"
241 select CRYPTO_SHA256
242
243config MODULE_SIG_SHA384
244 bool "Sign modules with SHA-384"
245 select CRYPTO_SHA512
246
247config MODULE_SIG_SHA512
248 bool "Sign modules with SHA-512"
249 select CRYPTO_SHA512
250
251config MODULE_SIG_SHA3_256
252 bool "Sign modules with SHA3-256"
253 select CRYPTO_SHA3
254
255config MODULE_SIG_SHA3_384
256 bool "Sign modules with SHA3-384"
257 select CRYPTO_SHA3
258
259config MODULE_SIG_SHA3_512
260 bool "Sign modules with SHA3-512"
261 select CRYPTO_SHA3
262
263endchoice
264
265config MODULE_SIG_HASH
266 string
267 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
268 default "sha256" if MODULE_SIG_SHA256
269 default "sha384" if MODULE_SIG_SHA384
270 default "sha512" if MODULE_SIG_SHA512
271 default "sha3-256" if MODULE_SIG_SHA3_256
272 default "sha3-384" if MODULE_SIG_SHA3_384
273 default "sha3-512" if MODULE_SIG_SHA3_512
274
275choice
276 prompt "Module compression mode"
277 help
278 This option allows you to choose the algorithm which will be used to
279 compress modules when 'make modules_install' is run. (or, you can
280 choose to not compress modules at all.)
281
282 External modules will also be compressed in the same way during the
283 installation.
284
285 For modules inside an initrd or initramfs, it's more efficient to
286 compress the whole initrd or initramfs instead.
287
288 This is fully compatible with signed modules.
289
290 Please note that the tool used to load modules needs to support the
291 corresponding algorithm. module-init-tools MAY support gzip, and kmod
292 MAY support gzip, xz and zstd.
293
294 Your build system needs to provide the appropriate compression tool
295 to compress the modules.
296
297 If in doubt, select 'None'.
298
299config MODULE_COMPRESS_NONE
300 bool "None"
301 help
302 Do not compress modules. The installed modules are suffixed
303 with .ko.
304
305config MODULE_COMPRESS_GZIP
306 bool "GZIP"
307 help
308 Compress modules with GZIP. The installed modules are suffixed
309 with .ko.gz.
310
311config MODULE_COMPRESS_XZ
312 bool "XZ"
313 help
314 Compress modules with XZ. The installed modules are suffixed
315 with .ko.xz.
316
317config MODULE_COMPRESS_ZSTD
318 bool "ZSTD"
319 help
320 Compress modules with ZSTD. The installed modules are suffixed
321 with .ko.zst.
322
323endchoice
324
325config MODULE_DECOMPRESS
326 bool "Support in-kernel module decompression"
327 depends on MODULE_COMPRESS_GZIP || MODULE_COMPRESS_XZ || MODULE_COMPRESS_ZSTD
328 select ZLIB_INFLATE if MODULE_COMPRESS_GZIP
329 select XZ_DEC if MODULE_COMPRESS_XZ
330 select ZSTD_DECOMPRESS if MODULE_COMPRESS_ZSTD
331 help
332
333 Support for decompressing kernel modules by the kernel itself
334 instead of relying on userspace to perform this task. Useful when
335 load pinning security policy is enabled.
336
337 If unsure, say N.
338
339config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
340 bool "Allow loading of modules with missing namespace imports"
341 help
342 Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
343 a namespace. A module that makes use of a symbol exported with such a
344 namespace is required to import the namespace via MODULE_IMPORT_NS().
345 There is no technical reason to enforce correct namespace imports,
346 but it creates consistency between symbols defining namespaces and
347 users importing namespaces they make use of. This option relaxes this
348 requirement and lifts the enforcement when loading a module.
349
350 If unsure, say N.
351
352config MODPROBE_PATH
353 string "Path to modprobe binary"
354 default "/sbin/modprobe"
355 help
356 When kernel code requests a module, it does so by calling
357 the "modprobe" userspace utility. This option allows you to
358 set the path where that binary is found. This can be changed
359 at runtime via the sysctl file
360 /proc/sys/kernel/modprobe. Setting this to the empty string
361 removes the kernel's ability to request modules (but
362 userspace can still load modules explicitly).
363
364config TRIM_UNUSED_KSYMS
365 bool "Trim unused exported kernel symbols" if EXPERT
366 depends on !COMPILE_TEST
367 help
368 The kernel and some modules make many symbols available for
369 other modules to use via EXPORT_SYMBOL() and variants. Depending
370 on the set of modules being selected in your kernel configuration,
371 many of those exported symbols might never be used.
372
373 This option allows for unused exported symbols to be dropped from
374 the build. In turn, this provides the compiler more opportunities
375 (especially when using LTO) for optimizing the code and reducing
376 binary size. This might have some security advantages as well.
377
378 If unsure, or if you need to build out-of-tree modules, say N.
379
380config UNUSED_KSYMS_WHITELIST
381 string "Whitelist of symbols to keep in ksymtab"
382 depends on TRIM_UNUSED_KSYMS
383 help
384 By default, all unused exported symbols will be un-exported from the
385 build when TRIM_UNUSED_KSYMS is selected.
386
387 UNUSED_KSYMS_WHITELIST allows to whitelist symbols that must be kept
388 exported at all times, even in absence of in-tree users. The value to
389 set here is the path to a text file containing the list of symbols,
390 one per line. The path can be absolute, or relative to the kernel
391 source tree.
392
393config MODULES_TREE_LOOKUP
394 def_bool y
395 depends on PERF_EVENTS || TRACING || CFI_CLANG
396
397endif # MODULES
1# SPDX-License-Identifier: GPL-2.0-only
2menuconfig MODULES
3 bool "Enable loadable module support"
4 modules
5 select EXECMEM
6 help
7 Kernel modules are small pieces of compiled code which can
8 be inserted in the running kernel, rather than being
9 permanently built into the kernel. You use the "modprobe"
10 tool to add (and sometimes remove) them. If you say Y here,
11 many parts of the kernel can be built as modules (by
12 answering M instead of Y where indicated): this is most
13 useful for infrequently used options which are not required
14 for booting. For more information, see the man pages for
15 modprobe, lsmod, modinfo, insmod and rmmod.
16
17 If you say Y here, you will need to run "make
18 modules_install" to put the modules under /lib/modules/
19 where modprobe can find them (you may need to be root to do
20 this).
21
22 If unsure, say Y.
23
24if MODULES
25
26config MODULE_DEBUGFS
27 bool
28
29config MODULE_DEBUG
30 bool "Module debugging"
31 depends on DEBUG_FS
32 help
33 Allows you to enable / disable features which can help you debug
34 modules. You don't need these options on production systems.
35
36if MODULE_DEBUG
37
38config MODULE_STATS
39 bool "Module statistics"
40 depends on DEBUG_FS
41 select MODULE_DEBUGFS
42 help
43 This option allows you to maintain a record of module statistics.
44 For example, size of all modules, average size, text size, a list
45 of failed modules and the size for each of those. For failed
46 modules we keep track of modules which failed due to either the
47 existing module taking too long to load or that module was already
48 loaded.
49
50 You should enable this if you are debugging production loads
51 and want to see if userspace or the kernel is doing stupid things
52 with loading modules when it shouldn't or if you want to help
53 optimize userspace / kernel space module autoloading schemes.
54 You might want to do this because failed modules tend to use
55 up significant amount of memory, and so you'd be doing everyone a
56 favor in avoiding these failures proactively.
57
58 This functionality is also useful for those experimenting with
59 module .text ELF section optimization.
60
61 If unsure, say N.
62
63config MODULE_DEBUG_AUTOLOAD_DUPS
64 bool "Debug duplicate modules with auto-loading"
65 help
66 Module autoloading allows in-kernel code to request modules through
67 the *request_module*() API calls. This in turn just calls userspace
68 modprobe. Although modprobe checks to see if a module is already
69 loaded before trying to load a module there is a small time window in
70 which multiple duplicate requests can end up in userspace and multiple
71 modprobe calls race calling finit_module() around the same time for
72 duplicate modules. The finit_module() system call can consume in the
73 worst case more than twice the respective module size in virtual
74 memory for each duplicate module requests. Although duplicate module
75 requests are non-fatal virtual memory is a limited resource and each
76 duplicate module request ends up just unnecessarily straining virtual
77 memory.
78
79 This debugging facility will create pr_warn() splats for duplicate
80 module requests to help identify if module auto-loading may be the
81 culprit to your early boot virtual memory pressure. Since virtual
82 memory abuse caused by duplicate module requests could render a
83 system unusable this functionality will also converge races in
84 requests for the same module to a single request. You can boot with
85 the module.enable_dups_trace=1 kernel parameter to use WARN_ON()
86 instead of the pr_warn().
87
88 If the first module request used request_module_nowait() we cannot
89 use that as the anchor to wait for duplicate module requests, since
90 users of request_module() do want a proper return value. If a call
91 for the same module happened earlier with request_module() though,
92 then a duplicate request_module_nowait() would be detected. The
93 non-wait request_module() call is synchronous and waits until modprobe
94 completes. Subsequent auto-loading requests for the same module do
95 not trigger a new finit_module() calls and do not strain virtual
96 memory, and so as soon as modprobe successfully completes we remove
97 tracking for duplicates for that module.
98
99 Enable this functionality to try to debug virtual memory abuse during
100 boot on systems which are failing to boot or if you suspect you may be
101 straining virtual memory during boot, and you want to identify if the
102 abuse was due to module auto-loading. These issues are currently only
103 known to occur on systems with many CPUs (over 400) and is likely the
104 result of udev issuing duplicate module requests for each CPU, and so
105 module auto-loading is not the culprit. There may very well still be
106 many duplicate module auto-loading requests which could be optimized
107 for and this debugging facility can be used to help identify them.
108
109 Only enable this for debugging system functionality, never have it
110 enabled on real systems.
111
112config MODULE_DEBUG_AUTOLOAD_DUPS_TRACE
113 bool "Force full stack trace when duplicates are found"
114 depends on MODULE_DEBUG_AUTOLOAD_DUPS
115 help
116 Enabling this will force a full stack trace for duplicate module
117 auto-loading requests using WARN_ON() instead of pr_warn(). You
118 should keep this disabled at all times unless you are a developer
119 and are doing a manual inspection and want to debug exactly why
120 these duplicates occur.
121
122endif # MODULE_DEBUG
123
124config MODULE_FORCE_LOAD
125 bool "Forced module loading"
126 default n
127 help
128 Allow loading of modules without version information (ie. modprobe
129 --force). Forced module loading sets the 'F' (forced) taint flag and
130 is usually a really bad idea.
131
132config MODULE_UNLOAD
133 bool "Module unloading"
134 help
135 Without this option you will not be able to unload any
136 modules (note that some modules may not be unloadable
137 anyway), which makes your kernel smaller, faster
138 and simpler. If unsure, say Y.
139
140config MODULE_FORCE_UNLOAD
141 bool "Forced module unloading"
142 depends on MODULE_UNLOAD
143 help
144 This option allows you to force a module to unload, even if the
145 kernel believes it is unsafe: the kernel will remove the module
146 without waiting for anyone to stop using it (using the -f option to
147 rmmod). This is mainly for kernel developers and desperate users.
148 If unsure, say N.
149
150config MODULE_UNLOAD_TAINT_TRACKING
151 bool "Tainted module unload tracking"
152 depends on MODULE_UNLOAD
153 select MODULE_DEBUGFS
154 help
155 This option allows you to maintain a record of each unloaded
156 module that tainted the kernel. In addition to displaying a
157 list of linked (or loaded) modules e.g. on detection of a bad
158 page (see bad_page()), the aforementioned details are also
159 shown. If unsure, say N.
160
161config MODVERSIONS
162 bool "Module versioning support"
163 depends on !COMPILE_TEST
164 help
165 Usually, you have to use modules compiled with your kernel.
166 Saying Y here makes it sometimes possible to use modules
167 compiled for different kernels, by adding enough information
168 to the modules to (hopefully) spot any changes which would
169 make them incompatible with the kernel you are running. If
170 unsure, say N.
171
172config ASM_MODVERSIONS
173 bool
174 default HAVE_ASM_MODVERSIONS && MODVERSIONS
175 help
176 This enables module versioning for exported symbols also from
177 assembly. This can be enabled only when the target architecture
178 supports it.
179
180config MODULE_SRCVERSION_ALL
181 bool "Source checksum for all modules"
182 help
183 Modules which contain a MODULE_VERSION get an extra "srcversion"
184 field inserted into their modinfo section, which contains a
185 sum of the source files which made it. This helps maintainers
186 see exactly which source was used to build a module (since
187 others sometimes change the module source without updating
188 the version). With this option, such a "srcversion" field
189 will be created for all modules. If unsure, say N.
190
191config MODULE_SIG
192 bool "Module signature verification"
193 select MODULE_SIG_FORMAT
194 help
195 Check modules for valid signatures upon load: the signature
196 is simply appended to the module. For more information see
197 <file:Documentation/admin-guide/module-signing.rst>.
198
199 Note that this option adds the OpenSSL development packages as a
200 kernel build dependency so that the signing tool can use its crypto
201 library.
202
203 You should enable this option if you wish to use either
204 CONFIG_SECURITY_LOCKDOWN_LSM or lockdown functionality imposed via
205 another LSM - otherwise unsigned modules will be loadable regardless
206 of the lockdown policy.
207
208 !!!WARNING!!! If you enable this option, you MUST make sure that the
209 module DOES NOT get stripped after being signed. This includes the
210 debuginfo strip done by some packagers (such as rpmbuild) and
211 inclusion into an initramfs that wants the module size reduced.
212
213config MODULE_SIG_FORCE
214 bool "Require modules to be validly signed"
215 depends on MODULE_SIG
216 help
217 Reject unsigned modules or signed modules for which we don't have a
218 key. Without this, such modules will simply taint the kernel.
219
220config MODULE_SIG_ALL
221 bool "Automatically sign all modules"
222 default y
223 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
224 help
225 Sign all modules during make modules_install. Without this option,
226 modules must be signed manually, using the scripts/sign-file tool.
227
228comment "Do not forget to sign required modules with scripts/sign-file"
229 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
230
231choice
232 prompt "Hash algorithm to sign modules"
233 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
234 help
235 This determines which sort of hashing algorithm will be used during
236 signature generation. This algorithm _must_ be built into the kernel
237 directly so that signature verification can take place. It is not
238 possible to load a signed module containing the algorithm to check
239 the signature on that module.
240
241config MODULE_SIG_SHA1
242 bool "SHA-1"
243 select CRYPTO_SHA1
244
245config MODULE_SIG_SHA256
246 bool "SHA-256"
247 select CRYPTO_SHA256
248
249config MODULE_SIG_SHA384
250 bool "SHA-384"
251 select CRYPTO_SHA512
252
253config MODULE_SIG_SHA512
254 bool "SHA-512"
255 select CRYPTO_SHA512
256
257config MODULE_SIG_SHA3_256
258 bool "SHA3-256"
259 select CRYPTO_SHA3
260
261config MODULE_SIG_SHA3_384
262 bool "SHA3-384"
263 select CRYPTO_SHA3
264
265config MODULE_SIG_SHA3_512
266 bool "SHA3-512"
267 select CRYPTO_SHA3
268
269endchoice
270
271config MODULE_SIG_HASH
272 string
273 depends on MODULE_SIG || IMA_APPRAISE_MODSIG
274 default "sha1" if MODULE_SIG_SHA1
275 default "sha256" if MODULE_SIG_SHA256
276 default "sha384" if MODULE_SIG_SHA384
277 default "sha512" if MODULE_SIG_SHA512
278 default "sha3-256" if MODULE_SIG_SHA3_256
279 default "sha3-384" if MODULE_SIG_SHA3_384
280 default "sha3-512" if MODULE_SIG_SHA3_512
281
282config MODULE_COMPRESS
283 bool "Module compression"
284 help
285 Enable module compression to reduce on-disk size of module binaries.
286 This is fully compatible with signed modules.
287
288 The tool used to work with modules needs to support the selected
289 compression type. kmod MAY support gzip, xz and zstd. Other tools
290 might have a limited selection of the supported types.
291
292 Note that for modules inside an initrd or initramfs, it's more
293 efficient to compress the whole ramdisk instead.
294
295 If unsure, say N.
296
297choice
298 prompt "Module compression type"
299 depends on MODULE_COMPRESS
300 help
301 Choose the supported algorithm for module compression.
302
303config MODULE_COMPRESS_GZIP
304 bool "GZIP"
305 help
306 Support modules compressed with GZIP. The installed modules are
307 suffixed with .ko.gz.
308
309config MODULE_COMPRESS_XZ
310 bool "XZ"
311 help
312 Support modules compressed with XZ. The installed modules are
313 suffixed with .ko.xz.
314
315config MODULE_COMPRESS_ZSTD
316 bool "ZSTD"
317 help
318 Support modules compressed with ZSTD. The installed modules are
319 suffixed with .ko.zst.
320
321endchoice
322
323config MODULE_COMPRESS_ALL
324 bool "Automatically compress all modules"
325 default y
326 depends on MODULE_COMPRESS
327 help
328 Compress all modules during 'make modules_install'.
329
330 Your build system needs to provide the appropriate compression tool
331 for the selected compression type. External modules will also be
332 compressed in the same way during the installation.
333
334config MODULE_DECOMPRESS
335 bool "Support in-kernel module decompression"
336 depends on MODULE_COMPRESS
337 select ZLIB_INFLATE if MODULE_COMPRESS_GZIP
338 select XZ_DEC if MODULE_COMPRESS_XZ
339 select ZSTD_DECOMPRESS if MODULE_COMPRESS_ZSTD
340 help
341 Support for decompressing kernel modules by the kernel itself
342 instead of relying on userspace to perform this task. Useful when
343 load pinning security policy is enabled.
344
345 If unsure, say N.
346
347config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
348 bool "Allow loading of modules with missing namespace imports"
349 help
350 Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
351 a namespace. A module that makes use of a symbol exported with such a
352 namespace is required to import the namespace via MODULE_IMPORT_NS("").
353 There is no technical reason to enforce correct namespace imports,
354 but it creates consistency between symbols defining namespaces and
355 users importing namespaces they make use of. This option relaxes this
356 requirement and lifts the enforcement when loading a module.
357
358 If unsure, say N.
359
360config MODPROBE_PATH
361 string "Path to modprobe binary"
362 default "/sbin/modprobe"
363 help
364 When kernel code requests a module, it does so by calling
365 the "modprobe" userspace utility. This option allows you to
366 set the path where that binary is found. This can be changed
367 at runtime via the sysctl file
368 /proc/sys/kernel/modprobe. Setting this to the empty string
369 removes the kernel's ability to request modules (but
370 userspace can still load modules explicitly).
371
372config TRIM_UNUSED_KSYMS
373 bool "Trim unused exported kernel symbols"
374 help
375 The kernel and some modules make many symbols available for
376 other modules to use via EXPORT_SYMBOL() and variants. Depending
377 on the set of modules being selected in your kernel configuration,
378 many of those exported symbols might never be used.
379
380 This option allows for unused exported symbols to be dropped from
381 the build. In turn, this provides the compiler more opportunities
382 (especially when using LTO) for optimizing the code and reducing
383 binary size. This might have some security advantages as well.
384
385 If unsure, or if you need to build out-of-tree modules, say N.
386
387config UNUSED_KSYMS_WHITELIST
388 string "Whitelist of symbols to keep in ksymtab"
389 depends on TRIM_UNUSED_KSYMS
390 help
391 By default, all unused exported symbols will be un-exported from the
392 build when TRIM_UNUSED_KSYMS is selected.
393
394 UNUSED_KSYMS_WHITELIST allows to whitelist symbols that must be kept
395 exported at all times, even in absence of in-tree users. The value to
396 set here is the path to a text file containing the list of symbols,
397 one per line. The path can be absolute, or relative to the kernel
398 source or obj tree.
399
400config MODULES_TREE_LOOKUP
401 def_bool y
402 depends on PERF_EVENTS || TRACING || CFI_CLANG
403
404endif # MODULES